INVEST Model

Overview

INVEST is an acronym used to evaluate the quality of user stories in agile development. A well-written user story should satisfy all six criteria.

Criteria

I – Independent

User stories should be self-contained and not depend on other stories. This allows teams to prioritize and implement them in any order without external blockers.

N – Negotiable

Stories are not rigid contracts. The details should remain open to discussion between the team and stakeholders until the story is committed to a sprint.

V – Valuable

Every story must deliver clear value to the end user or the business. If a story does not provide a tangible benefit, it should be reconsidered or removed.

E – Estimable

The team must be able to estimate the effort required to implement the story. Stories that cannot be estimated are usually too vague, too large.

S – Small

Stories should be small enough to be completed within a single sprint. Large stories (epics) must be broken down into smaller, manageable pieces before implementation.

T – Testable

A story must have clear acceptance criteria that allow the team to verify whether the implementation is correct and complete.

Summary

Letter	Criterion	Key Question
I	Independent	Can this be implemented without other stories?
N	Negotiable	Is it debatable until it can be implemented?
V	Valuable	Does this deliver value to the user?
E	Estimable	Can we estimate the effort to implement this?
S	Small	Can this be completed within one sprint?
T	Testable	Do we have clear acceptance criteria?